1. Field of the Invention
The present invention relates to optical processing apparatus, particularly of the holographic type.
2. Discussion of the Prior Art
Image processing, including holograms, is usually handled through rectangular arrays of photoelements, such as gallium arsenide light-emitting diodes and photoreceptors of various types. Usually, each photoreceptor or emitting diode corresponds to a single pixel (picture element) in the image being processed. It is desired to have apparatus that can quickly process a large number of images with a minimal physical motion of apparatus and with a minimum number of photoelements. Accordingly, it is desired to have a single array of light-emitting diodes for processing all images and a single receptor array for receiving all images.
The IBM TECHNICAL DISCLOSURE BULLETIN, April 1969, Vol. 11-No. 11, pp. 1392-3, shows a single gallium arsenide diode array which is switched electronically for directing readout beams through suitable optics to a transmissive hologram or record medium. A single-receiving photo array disposed on the opposite side of the hologram plate from the gallium arsenide diode array receives the transmitted image. While this arrangement provides for switching between holograms stored in a hologram storing plate, it does not provide for efficient volumetric storage of holograms, i.e., the overlaying of holograms within an electro-optic material, such as bismuth silicon oxide. A limitation of this disclosed apparatus is the density of holograms.
U.S. Pat. No. 3,284,799 (K. F. Ross) shows arrays of amplitude detectors which receive reflected signals from a single source and commutate same through electronic scanners. Electronic scanners focus the beam being processed onto an elliptically-concave mirror which has a curvature matched with a reflector for directing all of the beams to a single detector. While this apparatus shows a single transmitter and a single receiver, it does not illustrate how to gain access to a plurality of images which may be stored in a suitable storage medium. Similarly, McAdam (U.S. Pat. No. 3,364,497) shows a linear array of mirrors reflecting light from a single source for generating an interference pattern. This patent does not suggest how to efficiently multiplex a plurality of holograms.